Close to a third of Maryland workers who filed injury compensation claims in recent years continued to rely on highly addictive opioid painkillers three months after they were hurt, according to a recent study by University of Maryland School of Medicine researchers.

Excessive use of painkillers such as OxyContin and Vicodin, along with use of the illegal opioids heroin and fentanyl, has been cited in the opioid overdose crisis around the nation that has led to tens of thousands of deaths a year.

The researchers combed through data from nearly 9,600 people who filed claims from 2008 through 2016 through Chesapeake Employers’ Insurance Company in Maryland.

They wanted to better understand how many injured workers may be dependent on opioids and what characteristics they shared so better interventions could be developed to stem the overdose epidemic.

The study, published last month in JAMA Network Open, concluded that there were specific workers at high-risk for dependence and perhaps some should not have been given opioid prescriptions. Researchers found that workers who were age 60 or older, earned at least $60,000 and suffered strain, sprain and crush injuries were more likely to keep refilling their opioid prescriptions.

“The findings suggest workers’ compensation claimants have a high proportion of persistent opioid use,” the researchers wrote in the study. “Interventions to lower persistent opioid use among this population should target patients with the identified factors, and since persistent opioid use does not correlate with injury severity, consideration should be given to not initiating opioid use for non-severe injuries.”

The number of people fatally overdosing on prescription opioids in Maryland has been dropping as deaths from potent illegal forms of opioids grows, according to recent reports from state health officials. Prescription opioids still are considered a gateway to dependence for many people, who may turn to street drugs when they can no longer get a prescription from their doctors.